/*
 * This file is part of espanso.
 *
 * Copyright (C) 2019-2022 Federico Terzi
 *
 * espanso is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * espanso is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with espanso.  If not, see <https://www.gnu.org/licenses/>.
 */

use std::{
    collections::HashMap,
    path::{Path, PathBuf},
    process::{Command, Output},
    sync::LazyLock,
};

use super::exec_util::{determine_default_macos_shell, MacShell};
use crate::{Extension, ExtensionOutput, ExtensionResult, Params, Value};
use log::{debug, error, info};
use thiserror::Error;

#[allow(clippy::upper_case_acronyms)]
pub enum Shell {
    Bash,
    Cmd,
    Nu,
    Powershell, // Windows PowerShell (v1.0 - v5.1)
    Pwsh,       // PowerShell Core (v6.0+)
    Sh,
    WSL,
    WSL2,
    Zsh,
}

impl Shell {
    fn execute_cmd(
        &self,
        cmd: &str,
        vars: &HashMap<String, String>,
        override_path_on_macos: bool,
    ) -> std::io::Result<Output> {
        let mut is_wsl = false;

        let mut command = match self {
            Self::Bash => {
                let mut command = Command::new("bash");
                command.args(["-c", cmd]);
                command
            }
            Self::Cmd => {
                let mut command = Command::new("cmd");
                command.args(["/C", cmd]);
                command
            }
            Self::Nu => {
                let mut command = Command::new("nu");
                command.args(["--commands", cmd]);
                command
            }
            Self::Powershell => {
                let mut command = Command::new("powershell");
                command.args(["-Command", cmd]);
                command
            }
            Self::Pwsh => {
                let mut command = Command::new("pwsh");
                command.args(["-Command", cmd]);
                command
            }
            Self::Sh => {
                let mut command = Command::new("sh");
                command.args(["-c", cmd]);
                command
            }
            Self::WSL => {
                is_wsl = true;
                let mut command = Command::new("bash");
                command.args(["-c", cmd]);
                command
            }
            Self::WSL2 => {
                is_wsl = true;
                let mut command = Command::new("wsl");
                command.args(["bash", "-c", cmd]);
                command
            }
            Self::Zsh => {
                let mut command = Command::new("zsh");
                command.args(["-c", cmd]);
                command
            }
        };

        // Set the OS-specific flags
        super::util::set_command_flags(&mut command);

        // Inject all the previous variables
        for (key, value) in vars {
            command.env(key, value);
        }

        // If Espanso is executed as an app bundle on macOS, it doesn't inherit the
        // PATH environment variables that are available inside a terminal, and this
        // can be confusing for users.
        // For example, one might use "jq" inside the terminal but then it throws an
        // error with "command not found" if launched through the Espanso shell
        // extension. For this reason, Espanso tries to obtain the same PATH value by
        // spawning a login shell and extracting the PATH after the processing.
        if cfg!(target_os = "macos") && override_path_on_macos {
            let supported_mac_shell = match self {
                Self::Bash => Some(MacShell::Bash),
                Self::Nu => Some(MacShell::Nu),
                Self::Pwsh => Some(MacShell::Pwsh),
                Self::Sh => Some(MacShell::Sh),
                Self::Zsh => Some(MacShell::Zsh),
                _ => None,
            };
            if let Some(path_env_override) =
                super::exec_util::determine_path_env_variable_override(supported_mac_shell)
            {
                debug!("overriding PATH env variable with: {path_env_override}");
                command.env("PATH", path_env_override);
            }
        }

        // In WSL environment, we have to specify which ENV variables should be
        // passed to linux. For more information:
        // https://devblogs.microsoft.com/commandline/share-environment-vars-between-wsl-and-windows/
        if is_wsl {
            let mut tokens: Vec<&str> = vec!["CONFIG/p"];

            // Add all the previous variables
            for key in vars.keys() {
                tokens.push(key);
            }

            let wsl_env = tokens.join(":");
            command.env("WSLENV", wsl_env);
        }

        command.output()
    }

    fn from_string(shell: &str) -> Option<Self> {
        match shell {
            "bash" => Some(Self::Bash),
            "cmd" => Some(Self::Cmd),
            "nu" => Some(Self::Nu),
            "powershell" => Some(Self::Powershell),
            "pwsh" => Some(Self::Pwsh),
            "sh" => Some(Self::Sh),
            "wsl" => Some(Self::WSL),
            "wsl2" => Some(Self::WSL2),
            "zsh" => Some(Self::Zsh),
            _ => None,
        }
    }
}

impl Default for Shell {
    fn default() -> Self {
        if cfg!(target_os = "windows") {
            Self::Powershell
        } else if cfg!(target_os = "macos") {
            static DEFAULT_MACOS_SHELL: LazyLock<Option<MacShell>> =
                LazyLock::new(determine_default_macos_shell);

            match &*DEFAULT_MACOS_SHELL {
                Some(MacShell::Bash) => Self::Bash,
                Some(MacShell::Nu) => Self::Nu,
                Some(MacShell::Pwsh) => Self::Pwsh,
                Some(MacShell::Zsh) => Self::Zsh,
                None | Some(MacShell::Sh) => Self::Sh,
            }
        } else if cfg!(target_os = "linux") {
            Self::Bash
        } else {
            panic!("invalid target os for shell")
        }
    }
}

pub struct ShellExtension {
    config_path: PathBuf,
}

#[allow(clippy::new_without_default)]
impl ShellExtension {
    pub fn new(config_path: &Path) -> Self {
        Self {
            config_path: config_path.to_owned(),
        }
    }
}

impl Extension for ShellExtension {
    fn name(&self) -> &'static str {
        "shell"
    }

    fn calculate(
        &self,
        _: &crate::Context,
        scope: &crate::Scope,
        params: &Params,
    ) -> crate::ExtensionResult {
        if let Some(Value::String(cmd)) = params.get("cmd") {
            let shell = if let Some(Value::String(shell_param)) = params.get("shell") {
                if let Some(shell) = Shell::from_string(shell_param) {
                    shell
                } else {
                    return ExtensionResult::Error(
                        ShellExtensionError::InvalidShell(shell_param.clone()).into(),
                    );
                }
            } else {
                Shell::default()
            };

            let mut env_variables = super::util::convert_to_env_variables(scope);
            env_variables.insert(
                "CONFIG".to_string(),
                self.config_path.to_string_lossy().to_string(),
            );

            let macos_override_path = params
                .get("macos_override_path")
                .and_then(|v| v.as_bool())
                .copied()
                .unwrap_or(true);

            match shell.execute_cmd(cmd, &env_variables, macos_override_path) {
                Ok(output) => {
                    let output_str = String::from_utf8_lossy(&output.stdout);
                    let error_str = String::from_utf8_lossy(&output.stderr);

                    let debug = params
                        .get("debug")
                        .and_then(|v| v.as_bool())
                        .copied()
                        .unwrap_or(false);

                    if debug {
                        info!("debug information for command> {cmd}");
                        info!("exit status: '{}'", output.status);
                        info!("stdout: '{output_str}'");
                        info!("stderr: '{error_str}'");
                        info!(
                            "this debug information was shown because the 'debug' option is true."
                        );
                    }

                    if !output.status.success() {
                        error!(
                            "shell command exited with code: {} and error: {}",
                            output.status, error_str
                        );

                        return ExtensionResult::Error(
                            ShellExtensionError::ExecutionError(error_str.to_string()).into(),
                        );
                    }

                    let trim = params
                        .get("trim")
                        .and_then(|v| v.as_bool())
                        .copied()
                        .unwrap_or(true);

                    let output = if trim {
                        output_str.trim().to_owned()
                    } else {
                        output_str.to_string()
                    };

                    ExtensionResult::Success(ExtensionOutput::Single(output))
                }
                Err(error) => ExtensionResult::Error(
                    ShellExtensionError::ExecutionFailed(cmd.clone(), error.into()).into(),
                ),
            }
        } else {
            ExtensionResult::Error(ShellExtensionError::MissingCmdParameter.into())
        }
    }
}

#[derive(Error, Debug)]
pub enum ShellExtensionError {
    #[error("missing 'cmd' parameter")]
    MissingCmdParameter,

    #[error("invalid shell: `{0}` is not a valid one")]
    InvalidShell(String),

    #[error("could not execute command: '`{0}`', error: '`{1}`'")]
    ExecutionFailed(String, anyhow::Error),

    #[error("command reported error: '`{0}`'")]
    ExecutionError(String),
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::Scope;

    #[test]
    fn shell_not_trimmed() {
        let extension = ShellExtension::new(&PathBuf::new());

        let param = vec![
            (
                "cmd".to_string(),
                Value::String("echo \"hello world\"".to_string()),
            ),
            ("trim".to_string(), Value::Bool(false)),
        ]
        .into_iter()
        .collect::<Params>();
        if cfg!(target_os = "windows") {
            assert_eq!(
                extension
                    .calculate(&crate::Context::default(), &HashMap::default(), &param)
                    .into_success()
                    .unwrap(),
                ExtensionOutput::Single("hello world\r\n".to_string())
            );
        } else {
            assert_eq!(
                extension
                    .calculate(&crate::Context::default(), &HashMap::default(), &param)
                    .into_success()
                    .unwrap(),
                ExtensionOutput::Single("hello world\n".to_string())
            );
        }
    }

    #[test]
    fn shell_trimmed() {
        let extension = ShellExtension::new(&PathBuf::new());

        let param = vec![(
            "cmd".to_string(),
            Value::String("echo \"hello world\"".to_string()),
        )]
        .into_iter()
        .collect::<Params>();

        assert_eq!(
            extension
                .calculate(&crate::Context::default(), &HashMap::default(), &param)
                .into_success()
                .unwrap(),
            ExtensionOutput::Single("hello world".to_string())
        );
    }

    #[test]
    #[cfg(not(target_os = "windows"))]
    fn pipes() {
        let extension = ShellExtension::new(&PathBuf::new());

        let param = vec![(
            "cmd".to_string(),
            Value::String("echo \"hello world\" | cat".to_string()),
        )]
        .into_iter()
        .collect::<Params>();
        assert_eq!(
            extension
                .calculate(&crate::Context::default(), &HashMap::default(), &param)
                .into_success()
                .unwrap(),
            ExtensionOutput::Single("hello world".to_string())
        );
    }

    #[test]
    fn var_injection() {
        let extension = ShellExtension::new(&PathBuf::new());

        let param = if cfg!(not(target_os = "windows")) {
            vec![(
                "cmd".to_string(),
                Value::String("echo $ESPANSO_VAR1".to_string()),
            )]
            .into_iter()
            .collect::<Params>()
        } else {
            vec![
                (
                    "cmd".to_string(),
                    Value::String("echo %ESPANSO_VAR1%".to_string()),
                ),
                ("shell".to_string(), Value::String("cmd".to_string())),
            ]
            .into_iter()
            .collect::<Params>()
        };
        let mut scope = Scope::new();
        scope.insert("var1", ExtensionOutput::Single("hello world".to_string()));
        assert_eq!(
            extension
                .calculate(&crate::Context::default(), &scope, &param)
                .into_success()
                .unwrap(),
            ExtensionOutput::Single("hello world".to_string())
        );
    }

    #[test]
    fn invalid_command() {
        let extension = ShellExtension::new(&PathBuf::new());

        let param = vec![(
            "cmd".to_string(),
            Value::String("nonexistentcommand".to_string()),
        )]
        .into_iter()
        .collect::<Params>();
        assert!(matches!(
            extension.calculate(&crate::Context::default(), &HashMap::default(), &param),
            ExtensionResult::Error(_)
        ));
    }

    #[test]
    #[cfg(not(target_os = "windows"))]
    fn exit_error() {
        let extension = ShellExtension::new(&PathBuf::new());

        let param = vec![("cmd".to_string(), Value::String("exit 1".to_string()))]
            .into_iter()
            .collect::<Params>();
        assert!(matches!(
            extension.calculate(&crate::Context::default(), &HashMap::default(), &param),
            ExtensionResult::Error(_)
        ));
    }
}
